At first, Janet Parker was not overly concerned by the throbbing, stubborn headache. She even shrugged off the muscle pain that came in ever more intense spasms.

It was merely a cold, she told herself.

The rash that began to sweep Janet's body was the first indication that something was seriously wrong, the signpost to one of the Midlands' most harrowing health scares.

Janet's body was fighting a losing battle against a deadly, airborne disease that had been scrubbed from these shores years earlier.

The photographer at the University of Birmingham medical school was infected with smallpox. What's more, she had contracted the deadliest strain, Variola major. It ravaged her body in no time.

Janet, the last person in Britain to die from the disease, left work with a migraine on August 11, 1978. She died four weeks later.

It was the start of a health scare akin to plague proportions. Worried members of the public devoured the lurid tabloid headlines and checked for symptoms.

The cause of Janet's infection sent shockwaves through the medical profession. It was soon deduced that the virus had travelled through an airduct connecting a smallpox lab with Janet's office directly above.

The emergency would claim three lives, although Janet remained the virus's only direct victim. Her father died from the stress of being quarantined, while the academic who ran the lab, Professor Henry Bedson, committed suicide.

However, Janet's mother was diagnosed with smallpox, but survived.

The professor's guilt was understandable. To a degree, he was caught in a race against time: Bedson believed he was close to a breakthrough in the global battle against smallpox and the World Health Organisation shared that belief.

But smallpox research in Birmingham was winding down and the lab earmarked for closure.

Because of the lack of investment, researchers worked on a lethal, airborne virus without the safety net of airlocks, separate showers, changing facilities or special clothing.

Members of public queue to receive smallpox vaccination at the Public Health Department clinic immunisation department in Birmingham in 1978

Unbelievably, the virus was handled in the main lab, away from safety cabinets. In the race to make medical history, corners were being cut. It was a time bomb – and on August 11, 38 years ago, it started ticking.

Janet had actually been vaccinated against the disease 12 years earlier, but that defence had weakened to the point of ineffectiveness.

The 40-year-old from Kings Norton was an unlikely catalyst for mass panic. She was the ordinary housewife who unwittingly took the leading role in a real life horror story.

She was the only daughter of Frederick and Hilda Witcomb, of Myrtle Avenue, Kings Heath. She was married to Post Office engineer Joseph Parker and the couple lived near by in a neat Burford Park Road semi-detached house.

Janet cut her teeth as a photographer with West Midlands Police, then found employment as a medical photographer in the university medical school's anatomy department. It was a job that sealed her fate.

Janet's darkroom was immediately above Bedson's lab – as the professor's research reached its most dangerous. At the time, he was researching deadly smallpox mutations known as "whitepox viruses". Variola major, a strain almost unknown until it emerged in Somalia in 1977, was one of them.

Considering the disease's rarity, East Birmingham (now Heartlands) Hospital's Professor Alasdair Geddes and Dr Thomas Henry Flewett's correct diagnosis was remarkable. Within hours of being admitted with an unbearable headache at 3pm on August 20, they had detected the deadly strain of smallpox.

By 10pm, Janet, her entire body scarlet with the raging fever, was being taken by blue light ambulance to Catherine-de-Barnes Hospital, Solihull. The disused medical centre had been turned into an isolation unit.

By 11pm, the press had been tipped off that Birmingham could be in the grip of the deadly virus. At first the news met with disbelief, then shock, then cold panic.

In all, 500 people were isolated, including Janet's parents, at Catherine-de-Barnes. The authorities worked with a speed and unity that today's computer age would struggle to match.

Within hours of Janet being taken in, her parents, the ambulance driver who took her and 260 other people were isolated. Birmingham was braced for a plague.

On August 26, health officials, dressed as if to explore another planet, fumigated Janet's Burford Park Road home and car. On August 28, it was announced that 500 people had been quarantined in their own homes and ordered not to step outside for two weeks.

The world waited for the first signs of the deadly rash. But, incredibly, even workers at Professor Bedson's lab escaped infection.

Only Janet's mother was diagnosed with smallpox, but was successfully treated.

Father Frederick, aged 71, was believed clear, but died of a heart attack on September 5 while visiting his daughter. By now the paranoia over infection was so great that no post mortem examination was carried out.

Janet died on September 11 and even after her body succumbed to the virulent virus, smallpox continued to plague her.

Strict disease control measures were put in place for the funeral, with undertaker Ron Fleet recalling: "When the day of the funeral arrived, the cars were given an escort by unmarked police vehicles just in case there was an accident.

"The body had to be cremated because there was a chance the virus could have thrived in the ground if Mrs Parker had been buried. All other funerals were cancelled that day and the Robin Hood Crematorium was thoroughly cleaned afterwards."

Not the most conducive atmosphere to remember loved ones.

But this was a killer disease with a long fuse. The ward where Janet lay dying was sealed for five years.

A Government report into the outbreak was damning. The Shooter Report found several workers at the lab had not received the required special training. Bedson had misled the World Health Organisation, telling them the lab's work had steadily declined since 1973, when, in fact, he had cranked up operations considerably.

He had been engulfed in a race against time to finish his work before the lab was closed down.

It also found the very foundations of the disease that claimed Janet. The virus was called Abid, after the three-year-old boy from Pakistan it was sourced from. The report also declared the virus had travelled in air currents up a service duct from the laboratory below, to a room in the anatomy department that was used for telephone calls.

That, however, was rubbished during a 1979 court action by the Health and Safety Executive against the University of Birmingham for breach of safety laws.

Experts found there was not enough of the virus produced at the lab to cause death in the telephone room above. That would have required 11,812 gallons of the stuff hanging in the air – but the source was definitely the lab.

The university was found not guilty, but, following a claim for damages made by union Association of Scientific, Technical and Managerial Staffs in 1979, Parker's husband, Joseph, was awarded £25,000.